Revision pack for year 11 for SDME exam for OCR B specification 2016 exam. Rivers and Coasts.

1. GCSE Geography Revision
Pack : SDME
SDME (Rivers & Coasts): 24th May 2015
NAME:
RESOURCES BLOG: www.geogdebens.wordpress.com
OneDrive resources: http://1drv.ms/1MMaJD0
or Tweet @eggarsgeog
Geography Pods website - http://bit.ly/1lsJ4eG
BBC Bitesize site
Use the blog and
OneDrive resources
1

2. Rivers & Coasts
Rivers: Need to Know
Landforms:
• V-shape valleys
• Waterfalls & Gorges
• Meanders & Ox-bow lakes
• Floodplains, mouth & delta
Processes:
• Erosion, Transport, Deposition
Floods:
• Causes, impacts, prediction, management,
hydrographs
Case studies:
• LEDC flood: Zambezi, MEDC flood: Brisbane
Coasts: Need to Know
Landforms:
• Headlands & bays
• Wave cut platforms
• Caves, arches, stacks and stumps
• Beaches, spits, bars, tombolos
Processes:
• Erosion, Transport, Deposition
Coastal management:
• Hard vs soft engineering, sustainability,
advantages and disadvantages
Case studies:
• Landforms: e.g. Hengistbury Head
• Management: e.g. Barton-on-Sea &
Highcliffe, Hengistbury Head 2

3. Rivers Key terms : match up
1. Attrition
2. Abrasion
3. Hydraulic Action
4. Corrosion
5. Meander
6. Oxbow lake
7. Undercutting
8. Traction
9. Saltation
10. Suspension
11. Hydrological cycle
a. The process of heavy material being dragged
along the bottom of the river bed
b. A bend in the river
c. When chemicals in water acts like an acid to
dissolve sediment
d. When material is bounced along the bottom
of the river bed, picked up and dropped
e. When a meander is cut off to form a lake
f. The act of particles & water smoothing
sediment as if like sandpaper
g. The cycle of water around our planet in
solid, liquid and gas form
h. When small particles of rock dissolve into
water or float along river
i. When water and air are forced into
weaknesses in rock and split rocks apart
j. When splashback from water creates
notches and weaknesses at the base of
waterfalls, river banks or gorges
k. When particles in water are smashed into
other rocks to chip off pieces
3

4. V-Shape Valleys & Interlocking Spurs
Vertical erosion occurs in the upper course of the river. The river is steep and gravity pulls it downhill so
it erodes deeply in to the soil. The rocks on the valley sides slide down to make a V shape. Interlocking
spurs are like a zip. The river does not have the energy to erode the harder spurs of rock so it flows
around them, leaving harder rock spurs sticking out while softer rock erodes in.
Meanders:
You get curves and bends as the river flows around harder rock. Water is fastest on the outside edge of
the bend so erodes more, it is slower on the inside and so deposits here. Over time these bends get
larger and larger, until they might be cut through during a storm.
Oxbow lakes
Are cut-off meanders.
When meanders get too large their ‘neck’ becomes tight and the water really slows down so too much
deposition occurs. Then when a storm happens a new fast straight channel is eroded straight past,
cutting off the old bend which gets left behind as a lake. Over time this lake dries up.
FLOODPLAINS
The area of land either side of the river in the lower course that gets flooded.
Very fertile and flat land because of rich soils that get deposited after floods.
Mouth:
The end of a river where it flows into a lake or the sea. The mouth might form an estuary or a delta.
Delta:
A deposition landform. Usually triangular shaped. When the river reaches the sea the water slows
down rapidly and deposits its material. The load builds up and the river gets broken up into lots of
smaller tributaries.
Estuary:
The deep and wider end of a river when it enters the sea. Water from the sea may flow up into the river
at high tide.
4

5. • Complete:
– The hard, surface rock is eroded more slowly and so is left unsupported as the underlying
_____ rock is more quickly by the river. In time this rock ledge will
collapse due to . This material will be swirled around by the river, widening and
the plunge pool at the foot of the waterfall. Eventually as more rock collapses, the
will retreat inland leaving a steep gorge.
waterfall deepening gravity
eroded resistant softer
5

6. Meanders Explanation
When rivers flow over flatter land, they develop large
bends called . As a river
goes around a most of the water is
pushed towards the outside causing increased
. The river is now eroding
into its banks rather than downwards into its bed, a
process called erosion. On the inside of
a bend there is much less water. Therefore the river is
shallow and slow-flowing. It cannot carry as much
and so sand a shingle will be
.
deposited meanders erosion
bend sideways lateral material
Ox-Bow Lake Explanation
As the river gets closer to its mouth it develops larger _________ .
Water in the river flows fastest on the ________ of the bend, and so
erodes more deeply forming a steep river _______. Deposition occurs
______ the meander where water is slower. Over time, the meander
gets tighter and the loop becomes narrower at the bend. During peak
flow, like during a _______, the river runs so fast that water cuts right
across the meander to form a new straight channel. Water now flows
fastest in the middle of the _______ so ________ occurs on both banks.
Eventually, the old meander bend becomes _________ off with
sediment to leave the crescent-shaped ox-bow lake isolated. It may dry
up in time.
cliff storm meanders outside blocked
deposition channel inside 6

7. What features can you tell from a map?
7

8. The Flood / Storm Hydrograph
•Hydrographs are used to show the relationship between
precipitation and discharge (the amount of water
passing in the river channel).
•Hydrographs are used to predict whether a river is likely
to flood.
•Discharge is measured in Cumecs (cubic metres of
water per second).
•Lag Time is the delay between peak
precipitation and peak river discharge. The
lag time is critical to show whether a river
might flood.
•Short Lag Times means water enters the
river system very quickly following rainfall =
more likely to flood
•Long Lag Times means water takes a longer
time to enter the river system following rainfall
= less likely to flood
This could be for an
urban location,
quick surface runoff
and less infiltration
This could be for a
rural location, slow
surface runoff and
more infiltration
8

9. •Shortlagtimes=arecausedbysteepslopes,impermeablerock,sparsevegetationandasmall
drainagebasin.Thesemeansurfacerun-offishighsowaterenterstheriverquicklyfollowing
precipitation.
•Longlagtimes=arecausedbygentleslopes,permeablerock,densevegetationandalarge
drainagebasin.Thesemeansurfacerun-offislower,thereismoreinterceptionandinfiltrationso
watertakeslongertogettotheriverchannel.
Lagtimesareshortifwatercannotinfiltrateorisnotintercepted,itmeanswaterfromprecipitationis
enteringtheriverflowveryquickly+thereismoresurfacerunoff,e.g.Couldbeanurbandrainagebasin
Lagtimesarelongerifwatercaninfiltrateorgetsintercepted,itmeanswateristakinglongertoenterthe
riverchannel+thereislesssurfacerunoff,e.g.Couldbearuraldrainagebasin
9

10. Heavy rainfall = more water entering the river
catchment more quickly
River engineering = building bridges / dams /
channels changes how the river flows, and can
cause blockages
Ploughing = ploughing up + down channels in
fields creates artificial channels that allows water
to flow faster
Steep slopes = increases surface runoff before
infiltration and speeds up the river
Antecedent rainfall = previous rainfall means
ground is saturated so less infiltration + more
surface runoff
Urbanisation = impermeable surfaces so more
surface runoff
Deforestation = reduces interception so more
surface runoff, also means soil flows into river
which clogs it up
Hot dry weather = hard baked soil reduces
infiltration and increases surface runoff
Snow melt = more water input to the system Impermeable rocks = less infiltration/
groundwater flow and more surface runoff
Physical & human causes of river flooding
Flooding occurs when a river can not remove water from its channel as quickly as needed to empty it. So
flooding occurs if water input increases, or if river flow is less efficient.
So anything that reduces infiltration and increases surface runoff will cause flood risk.
10

11. 11

12. LEDC Case Study: The River Zambezi Floods (CAUSES), 2009
Deforestation within the
drainage basin So what?
e.g. Therefore this meant less
interception and water storage,
therefore more surface runoff and
short lag times
Soil erosion due to drought
and overgrazing So what?
Dams have been build along
the Zambezi So what?
Climate change So what?
The rainy season in the area usually
lasts 4-6 months. In 2009 the rain
was heavier than usual and lasted
for longer.
So what?
e.g. Therefore this meant soils
were saturated therefore less
infiltration and more surface runoff
Drainage systems we
unable to handle the huge
volumes of water
So what?
12

13. LEDC CASE STUDY River Zambezi 2009 floods Effects
River levels rose by 8 meters, record
levels not recorded since 1963.
Flood water quickly inundated houses
and villages in the Okavango and
Caprivi regions. Huts were constructed
from mud and straw and located within
the flood plain.
700,000 people, or 33% of the total
population of Namibia, were affected by
the flooding
50,000 people we displaced from their
homes.
102 people lost their lives. Villages were cut off by the floodwater.
N$1.1 billion (US$136.4 million) of
economic assets were lost and the
economy reduced by a further N$637
million.
9,000 people were relocated to camps.
These camps had insufficient water
supplies and inadequate sanitation
facilities. In one camp 4000 people
shared two latrines.
The local authorities were unable to
response to the scale of the disaster
Major road access was cut in northern
Caprivi at four locations, limiting access
to health clinics.
Only four out of eleven health clinics
were functioning immediately following
the disaster.
Local relief efforts were hampered by
poor information from the Zambezi River
Basin Authority.
Urban areas were also affected. Cities
in Ohangweena and Oshakiti saw
pumping stations fail and flood water
mixed with sewerage.
Higher water levels boosted fisheries as
more fish became available.
45,000ha of agricultural land was
destroyed and 3,000 livestock (mainly
goats) were lost. Farming is the main
economic activity in the flooded areas.
On March 2009 the
President of the Republic of
Namibia declared a state of
emergency.
The Government allocated
N$109 million (US$13million)
for the response.
110 relocation camps were
established.
International Aid was donated
the Namibia with the UN
sending approximately $4.2
Million. A total of US$7 million
was donated.
Human Response
13

14. MEDC case study: Brisbane floods
• Brisbane River, Queensland, Australia.
• January 2011
• Causes – Tropical Cyclone Tasha (natural hazard) & La Nina event (weather event
that brings prolonged heavy rains – wettest December ever, 209mm of rainfall in
December & raised sea level), some also blame sea level temperature rise
Response:
 Military evacuation of thousands of people
 Emergency Management Queensland in charge
 Metal flood barriers near Rockhampton
 Closed airports / highways / ports
 Evacuation centres in universities / schools
 Thousands of volunteers to help clear up / search and rescue as well as Fire Brigade
/ Police
 Raised over $40million in aid in the first two weeks
14

15. ¾ of Queensland state
declared a disaster zone.
70 towns flooded, 200’000
people affected
Panic – food supplies low,
looting
Over 25,000 homes were
flooding in Brisbane.
43 people died in incidents
related to the flooding.
30 suburbs were flooded in
Brisbane.
Estimates suggest Australia’s
GDP will be reduced by A$30
billion (£18.64 billion) due to
the floods.
An area larger than France and
Germany combined was under
water.
As the floods receded, putrid
mud and debris was left
throughout the city creating
health hazards.
$3billion in damages. Australia
is the world’s largest
exporter of coking coal, used in
steel production. Much of it
comes from Queensland’s
mines, many of which were
flooded.
Over 100,000 properties had
their electricity cut off as a
precaution against the flooding
of electricity substations.
Australia is the world’s 4th
largest exporter of wheat. The
rain damaged the crop so the
wheat could not be used for
bread and was downgraded to
use as animal feed, causing
heavy losses for farmers.
MEDC Case Study: Brisbane Floods 2011
15

16. River management: Hard + Soft Engineering
Hard Engineering Soft Engineering
Dams Wash lands
Embankments Land-use
zoning
Flood Walls Afforestation
Straightening and
deepening the river
Warning
systems
Storage areas Ensure you can evaluate the advantages and
disadvantages of each scheme.
Be able to evaluate sustainability in social, economic
and environmental sense. 16

17. Coastal Key terms : match up
1. Attrition
2. Abrasion
3. Hydraulic Action
4. Corrosion
5. Spit
6. Tombolo
7. Undercutting
8. Rotational cliff slumping
9. Longshore drift
10. Deposition
a. The process of material being moved along
the beach by waves in direction of prevailing
wind
b. When material is dropped off by the waves
when they have too little energy
c. When chemicals in water acts like an acid to
dissolve sediment
d. When a headland collapses due to the base
being weakened
e. A deposition landform that is a curved
beach that extends out from a headland
f. The act of particles & water smoothing
sediment as if like sandpaper
g. An island that is joined to land by a spit
h. When water and air are forced into
weaknesses in rock and split rocks apart
i. When waves or rivers create notches and
weaknesses at the base of rocks
j. When particles in water are smashed into
other rocks to chip away or break apart
17

18. Coast The maximum distance over which waves can travel is known as the…
Fetch One of the erosion processes that involves large waves hurtling beach
material at a cliff is called……..
Abrasion The landform created along stretches of less resistant coastlines (i.e.
areas made of clay) are known as…….
Bays The name given to waves with a weak swash but strong backwash is……
Destructive The process that involves beach material being dropped is more
technically known as….
Deposition What is the name given to the predominant force affecting the coastal
landscape of the UK…….
Prevailing Winds The process that carries material up and down the beach is known
as…….
Long shore Drift What is the name of the process that carries / returns wave energy back
down the beach
Backwash The erosion process that breaks up large boulders into small particles by
bumping them against each other is known as…..
Attrition The areas of land left protruding into the sea as they are more resistant
to wave erosion are called…..
Headlands The force of waves compressing air into cracks in a cliff is an erosion
process called…
Hydraulic Action Coastlines can dissolved by salts and acids in seawater. This is also
known as….
Corrosion The narrow contact zone between land and sea is more commonly called
the…
Coasts: Match the keyword with its meaning
18

19. Waves & longshore drift
There are two main types of waves:
• Constructive vs Destructive
• Constructive waves build up the beach, whereas destructive waves remove
material and reduce the beach. They form different landforms.
Longshore drift: the
process of material
being moved along
coast by waves in
direction of prevailing
wind. Shapes beaches,
creates spits. 19

20. The geology of the coast affects how
much it is eroded.
This is differential erosion.
More resistant rocks (e.g. chalk) erode
more slowly than less resistant rocks (e.g.
clay, limestone)
This gives us BAYS
And HEADLANDS
Coastlines are made of alternating layers of harder
(more resistant) and softer (less resistant) rocks.
This geology influences what landforms are created.
20

21. • So how do cliffs and wave-cut platforms form?
- The erosion of a cliff is greatest at its base where large waves break - hydraulic action, abrasion and attrition
constantly undercut the foot of the cliff
- This forms a dent called a wave-cut notch
- The cliff face is also affected by abrasion as rock fragments are hurled against the cliff by the breaking waves.
- The undercutting continues and eventually the overhanging cliff becomes so heavy it collapses downwards -
this process continues over time and the cliff gradually retreats inland and becomes steeper.
- As the cliff retreats, a gently-sloping rocky platform is left at the base, this is known as a wave-cut platform
which is exposed at low tide.
21

22. 22

23. Deposition landforms: Beaches, spits, bars & tombolos
 Coasts are not just eroded, they are also built up by deposition – this
is when eroded material is dropped off and builds up over time
 This creates beaches
 Deposition happens when waves are constructive (so the swash is
bigger than backwash so material gets moved up on to the beach).
 Material is moved by the sea and can travel miles
 Beaches, spits, bars and tombolos are created by deposition and
transportation
 Beaches develop when the supply of sediment exceeds any sediment
lost through backwash and longshore drift. They can be steep shingle
or flatter sand.
 Where there is a change in the coastline e.g. a headland or an
estuary mouth, longshore drift may continue to deposit sediments
into the sea forming a spit. E.g. Mudeford Spit at Hengistbury Head
 Local currents and changes in wind direction may curve the end of
the spit landwards creating a hooked tip. This is a recurved spit.
 If a spit joins on to one part of the mainland to another it is called a
bar.
 Where a spit joins the mainland to an island a tombolo may be
created. The longest and best known tombolo in Britain is Chesil
beach.
23

24. Social
EnvironmentalEconomic
Why is there a need to protect the coast?
Must consider how people use the
coast.
Consider different stakeholder
groups, e.g. residents, tourists,
environmentalists, councils,
shopkeepers, etc.
The value of land influences how
important it is when making
decisions about management. It is a
case of weighing up the costs (e.g.
money, damage to land, negative
views) vs the benefits (e.g. saving
homes, providing leisure facilities,
positive views).

25. Types of
Coastal
Management
HARD
ENGINEERING
Hard engineering
options tend to be
expensive and
short-term.
They may also
have a high impact
on the landscape
or environment.
SOFT
ENGINEERING
Soft engineering
options are often
less expensive than
hard engineering
options.
They are usually
also more long-
term and
sustainable, with
less impact on the
environment.
Some coastlines are under threat of erosion causing cliffs to retreat and
beach material to be lost. Others are at risk from coastal flooding. In
many cases the decision has been made to try and reduce the erosion to
protect the coastline. This is called COASTAL MANAGEMENT.
Coastal Management = The attempt by humans to maintain the
natural features of the coast for their own advantage.

27. Coastal erosion & management at Highcliffe &
Barton-on-Sea (Case study)
• Highcliffe, in Dorset & Barton-on-Sea, in Hampshire are neighbours
• Beach management is a political issue. The two councils do not agree about
coastal management because each area has different values.
• Highcliffe has high value residential properties (over £500’000), especially
retirement homes (over £300’000 flats). Barton-on-Sea is not residential but
lower value camping.
• The geology at both is very soft. The cliffs are layers of sand and clay – very
soft rocks, un-resistant to erosion.
• What one council does to protect its coast, has a big impact on the other
coastline – e.g. groynes at Highcliffe trap sediment which starves beaches
downcoast at Barton, meaning they are more vulnerable to erosion
• In 1950, both areas were receding at 2metres per year due to cliff slumping.
• Highcliffe installed hard and soft engineering from 1970s (including rock
armour, rock groynes, cliff reshaping, beach replenishment, etc,.) to protect
valuable properties and businesses (to ‘hold the line’) whereas Barton
decided upon ‘managed retreat’ due to lower land value making it less cost
effective to employ other strategies. Rock armour groynes cost ~£50’000
each!
• However, managed retreat is sustainable long term once the cliff collapses as
this will then protect inland from erosion
27

28. What has happened here? Why?What has happened here? Why? What is this? Why has it been built? How does
it work?
Land use here:This is the border between Hampshire and Dorset. Why
is that important?:
Land use here:
Coastal Management along Highcliffe and Barton on Sea
Barton on Sea, Hampshire
Highcliffe, Dorset
28

29. Method name How does it work? Advantages – how
sustainable?
Disadvantages – how
sustainable?
Groynes
Sea Wall
Revetments
Rock Armour
Gabions
Beach replenishment
Beach reshaping
Managed Retreat
29

30. Example 9 mark question answer: Coastal management
“For a coastal area you have studied, describe and explain the impacts of erosion. Explain how this erosion has
been managed and comment on the sustainability of these.”
• Highcliffe is an area of coastline located in Dorset, with Barton-on-Sea in Hampshire next door. Both areas have
the same mixed geology of soft, unresistant clays and sands that erode easily.
• At Highcliffe, cliff recession had been a problem. In the 1950s, Highcliffe was retreating inland at a rate of
2metres per year due to rotational slumping as a result of erosion and weathering. This resulted in damage to
properties and pathways at the top of the cliffs. At Barton-on-Sea, the cliff line has retreated 80m inland since
1930 which has caused a loss of land but minimal damage to properties.
• The coastal management varies at each location, despite them being the same geology and same erosion
processes. Highcliffe uses the ‘hold the line’ method with Dorset council introducing a range of hard and soft
engineering to retain the cliff line in place and reduce further loss of land. There is rock armour at the base of
the cliff to retain the strength, as well as rock armour groynes to reduce the impact of longshore drift transport.
The cliffs have been reshaped and terraced to make them stronger and less likely to collapse. Additionally, the
cliff terraces have now got cliff drainage and vegetation in order to drain excess water away and hold the soils
together. These techniques combined help to retain the strength of the cliff, and are successfully reducing cliff
recession.
• In terms of sustainability, the techniques employed are very costly and require long term maintenance. Highcliffe
rock armour costs approximately £4000 per metre however is sustainable when compared to the cost of
potential damages and insurance claims in the area since the property values are high, e.g. retirement flats of
over £300’000 each and detached homes of £1million. The potential damages outweigh the costs of
management schemes. The scheme is socially beneficial since the area is protected for residential use and also
for tourism with walkways being preserved. However, the solutions are not necessarily environmentally
sustainable since the knock-on-consequences downcoast are severe. For example, rock groynes trap sediment
that would normally be transported by longshore drift along coast. This means that Barton-on-Sea and other
areas are starved of sediment and therefore more vulnerable to erosion such as hydraulic action where cliffs are
exposed. Barton-on-Sea adopted managed retreat, where land is left unprotected and allowed to be eroded.
Although short term this does lead to loss of land and appears unattractive actually long term this method will
be sustainable since the coastline will find a natural balance with the collapsed cliffs eventually forming a
protective platform to reduce future erosion.
30

31. The SDME paper
3 sections
• Section A = 10marks; usually 2-4marks and a 6mark
Q. These will tell you to refer to particular sources
so DO THIS!
• Section B = 14marks; usually 6 and 8marks each.
You must refer to the resources. Must write in full
sentences using PE.E.L. (Point Evidence Explain
Link) to get full marks
• Section C = 16marks essay. But weighted – so really
it is worth 32marks. Credit for using different
resources. Marks for SPaG.

32. SDME: it’s all about using the Resource
Booklet. It has the answers!
TIP – spend the first 20mins of the exam
JUST reading and analysing the resources.
Annotate them. Draw out key facts that
you can quote.

33. SDME TOP TIP – making links
between multiple resources to draw
conclusions is a high level skill
PLAN how you will do this before you
write your section 3 essay.
QUOTE fact from the resources.
Say ‘as shown in Figure 1…’
INCLUDE different points of view,
mention different stakeholders, e.g.
residents, councils, Environment
Agency, tourists, etc.

34. An awesome SDME essay will:
- Evaluate each option: positive and negative
- Explain the advantages of your chosen option
- Describe a disadvantage of your option (be balanced)
- Explain why you rejected the other options
- Consider stakeholder views (e.g. local residents,
government, World Bank, charities, World Health
Organisation, etc.)
- Explain why your option is sustainable & define what
sustainability means
Use lots of the resources to justify your decision. Quote.

35. Do you:
You must:
1) Make a decision and justify your choice
2) Explain why your decision is sustainable (use S.E.E.)
3) Consider the viewpoints of different groups of people
4) Explain why you rejected the other options
Rivers DME practise
Scenario:
The Yangtze River is home to the infamous Three Gorges Dam – the largest dam in the world.
During construction, 1.2 million people were made homeless and over 14billion tons of
concrete was used to build. Floods downstream have been reduced, but silt and sand is trapped
and this is starving downstream. The dam produces 3% of China’s electricity through
HydroElectric Power (HEP). However, as China becomes more developed there is an increased
need for energy and for rural populations to have access to electricity. There is also an
increased future flood risk due to climate change.
The government is trying to maintain a high quality of life whilst reducing the impact of floods.
OPTION A – increase the height
of the existing dam and the size
of the reservoir to reduce flood
risk and slightly increase the
amount of energy produced
through HEP
OPTION C – reduce flood risk
downstream through
afforestation and land use
zoning, but maintain the existing
dam as it is
OPTION B – build a new dam
further downstream that will
generate another 5% of China’s
electricity in order to support
Shanghai
The SDME exam essay question is
worth 16marks. It requires 3 well
developed P.E.E. paragraphs plus
explanation of what sustainability is,
and an evaluation / comparison of
different strategies.

36. Do you:
You must:
1) Make a decision and justify your choice
2) Explain why your decision is sustainable (use S.E.E.)
3) Consider the viewpoints of different groups of people
4) Explain why you rejected the other options
Coasts DME practise
Scenario:
You are a coastal planner responsible for the Highcliffe and Barton-on-Sea region.
Highcliffe already has groynes, gabions, drainage and cliff re-shaping, however Barton-on-
Sea is managed retreat. The current coastal management at Highcliffe requires constant
maintenance and financial investment. The two areas have different land uses and
priorities: Highcliffe has high value residential properties, while Barton-on-Sea has a small
campsite. You are under pressure to manage the area in a sustainable way: to benefit the
social, economic and environmental aspects of the area long-term.
Option A - Maintain existing
coastal management at both
areas to ‘toe the line’ at
Highcliffe and ‘do nothing’ at
Barton
Option C - Introduce groynes
and beach replenishment at
Barton-on-Sea
Option B - Suggest that the
groyne at Chewton Bunny
(Barton) is removed and
increase managed retreat
The SDME exam essay question is
worth 16marks. It requires 3 well
developed P.E.E. paragraphs plus
explanation of what sustainability is,
and an evaluation / comparison of
different strategies.